Wiper and Washer Systems: Description and Operation
FRONT WIPER AND WASHER SYSTEMSystem Description
- Front wiper relays (HIGH, LOW) are included in IPDM E/R (intelligent power distribution module engine room).
- Front wiper reverse relay is included in relay box-1. Refer to "ELECTRICAL UNITS LOCATION".
- Wiper switch (combination switch) is composed of a combination of 5 output terminals and 5 input terminals. Terminal combination status is read by BCM (body control module) when switch is turned ON.
- BCM controls front wiper LO, HI, and INT (intermittent) operation.
- IPDM E/R operates wiper motor according to CAN communication signals from BCM.
- Front wiper motor switches LOW speed to/from HIGH speed by BCM function to change polarity.
OUTLINE
Power is supplied at all times
- to ignition relay, located in IPDM E/R, from battery directly,
- through 50 A fusible link (letter F, located in fuse and fusible link block)
- to BCM terminal 55,
- through 10 A fuse [No. 21, located in fuse block (J/B)]
- to BCM terminal 42,
- through 30 A fuse (No. 73, located in IPDM E/R)
- to front wiper low relay, located in IPDM E/R
- to front wiper reverse relay terminal 5,
- through 15 A fuse (No. 78, located in IPDM E/R)
- to CPU (central processing unit) located in IPDM E/R,
- through 15 A fuse (No. 71, located in IPDM E/R)
- to CPU located in IPDM E/R.
With the ignition switch in the ON or START position, power is supplied
- to ignition relay, located in IPDM E/R,
- through 15 A fuse [No. 1, located in fuse block (J/B)]
- to BCM terminal 38,
- through 10 A fuse [No. 12, located in fuse block (J/B)]
- to front wiper reverse relay terminal 1,
- through 10 A fuse (No. 84, located in IPDM E/R)
- to front washer pump terminal 1
- to front wiper motor terminal 4.
Ground is supplied
- to BCM terminal 52
- through grounds M16 and M70,
- to IPDM E/R terminals 38 and 51
- through grounds E22 and E43,
- to combination switch terminal 12
- through grounds M16 and M70.
LOW SPEED WIPER OPERATION
When wiper switch is in the LO position, BCM detects low speed wiper ON signal by BCM wiper switch reading function.
BCM sends front wiper request signal (LO) with CAN communication line
- from BCM terminals 39 and 40
- to IPDM E/R terminals 49 and 50.
When IPDM E/R receives front wiper request signal (LO), it turns ON front wiper low relay, located in IPDM E/R, power is supplied
- through IPDM E/R terminal 23 and front wiper high relay and front wiper low relay
- to front wiper motor terminal 3.
Ground is supplied
- to front wiper motor terminal 1
- through front wiper reverse relay terminals 3 and 4
- through grounds E22 and E43.
With power and ground supplied, the front wiper motor operates at low speed.
HIGH SPEED WIPER OPERATION
When wiper switch is in the HI position, BCM detects high speed wiper ON signal by BCM wiper switch reading function.
BCM sends front wiper request signal (HI) with CAN communication line
- from BCM terminals 39 and 40
- to IPDM E/R terminals 49 and 50.
When IPDM E/R receives front wiper request signal (HI), it turns ON front wiper high relay (located in IPDM E/R) and front wiper reverse relay (located in relay box-1), power is supplied
- through IPDM E/R terminal 19
- through front wiper reverse relay terminals 5 and 3
- to front wiper motor terminal 1.
Ground is supplied
- to front wiper motor terminal 2
- to IPDM E/R terminal 31 and front wiper high relay and front wiper low relay
- to IPDM E/R terminal 38
- through grounds E22 and E43.
With power and ground supplied, the front wiper motor operates at high speed.
INTERMITTENT OPERATION
1. BCM detects ON/OFF status of intermittent operation dial position 1, 2 and 3 switched by wiper dial position to judge wiper dial position status.
2. BCM calculates intermittent operation interval time (second) from the vehicle speed signal received by combination meter through CAN communication line and the wiper dial position.
3. BCM switches front wiper request signal transmitted to IPDM E/R through CAN communication line from STOP to LO once at intervals of intermittent operation time.
4. IPDM E/R receives front wiper request signal (LO) once to turn ON front wiper main relay located in IPDM E/R. Then operates front wiper. IPDM E/R receives front wiper auto stop signal (stop) input from front wiper motor to turn OFF front wiper motor relay. IPDM E/R switches front wiper auto stop signal transmitted through CAN communication line from MOVE to STOP.
5. BCM receives front wiper auto stop signal (stop) to operate timer that determines intermittent operation interval time till next front wiper motor operation.
AUTO STOP OPERATION
With wiper switch turned OFF, wiper motor will continue to operate until wiper arms reach windshield base.
When wiper arms are not located at base of windshield with wiper switch OFF, ground is provided
- from IPDM E/R terminal 23
- to front wiper motor terminal 3, in order to continue wiper motor operation at low speed.
When wiper arms reach base of windshield, front wiper motor terminals 4 and 5 are connected
- to IPDM E/R terminal 32
- through front wiper motor terminals 4 and 5.
Then the IPDM E/R sends auto stop operation signal to BCM with CAN communication line.
When BCM receives auto stop operation signal, BCM sends wiper stop signal to IPDM E/R with CAN communication line.
IPDM E/R stops wiper motor. Wiper motor will then stop wiper arms at the STOP position.
WASHER OPERATION
When wiper switch is in front wiper washer position with ignition switch ON, BCM detects front wiper washer
signal by BCM wiper switch reading function (refer to "COMBINATION SWITCH READING FUNCTION"). Combination switch ground is supplied
- to front washer pump terminal 2
- through combination switch terminal 14
- to combination switch terminal 12
- through grounds M16 and M70.
With power and ground supplied, front washer pump is operated.
When BCM detects that front washer pump has operated for 0.4 seconds or longer, BCM operates front wiper motor for low speed.
When BCM detects washer switch is OFF, low speed operation cycles approximately 2 times and stops.
MIST OPERATION
When the wiper switch is turned to the MIST position, wiper low speed operation cycles once and then stops. For additional information about wiper operation under this condition, refer to "LOW SPEED WIPER OPERATION".
If the switch is held in the MIST position, low speed operation continues.
FAIL-SAFE FUNCTION
If an abnormality occurs in CAN communications, IPDM E/R holds the condition just before fail-safe status is initiated until ignition switch is turned OFF. (If wipers were operating in LO just before the initiation of fail-safe status, they continue to operate in LOW until ignition switch is turned OFF.)
COMBINATION SWITCH READING FUNCTION
Description
- BCM reads combination switch (wiper) status, and controls front wipers according to the results.
- BCM reads information of a maximum of 20 switches by combining five output terminals (OUTPUT 1-5) and five input terminals (INPUT 1-5).
Operation Description
- BCM activates transistors of output terminals (OUTPUT 1-5) periodically and allows current to flow in turn.
- If any (one or more) switches are turned ON, circuit of output terminals (OUTPUT 1-5) and input terminals (INPUT 1-5) becomes active.
- At this time, transistors of output terminals (OUTPUT 1-5) are activated to allow current to flow. When voltage of input terminals (INPUT 1-5) corresponding to that switch changes, interface in BCM detects voltage change, and BCM determines that the switch is ON.
BCM - Operation Table of Combination Switches
- BCM reads operation status of combination switch using combinations shown in table.
Sample Operation: (When Wiper Switch Turned to LO Position)
- When wiper switch is turned to LO position, front wiper LO contact in combination switch turns ON. At this time if OUTPUT 1 transistor is activated, BCM detects that voltage changes in INPUT 3.
- When BCM detects that voltage changes in INPUT 3 while OUTPUT 1 transistor is ON, it judges that front wiper switch is in LO position. Then BCM sends front wiper request signal (LO) to IPDM E/R using CAN communication.
- If BCM detects that voltage changes in INPUT 3 when OUTPUT 1 transistor is activated again, it recognizes that wiper switch is still in LO position.
NOTE: Each OUTPUT terminal transistor is activated at 10 ms intervals. Therefore after switch is turned ON, electrical loads are activated with time delay. But this time delay is so short that it cannot be detected by human senses.
Operation Mode
Combination switch reading function has operation modes shown here.
1. Normal status
- When BCM is not in sleep status, OUTPUT terminals (1-5) each turn ON-OFF every 10 ms.
2. Sleep status
- When BCM is in sleep status, transistors of OUTPUT 1 and 5 stop the output, and BCM enters low current consumption mode. OUTPUT 2, 3, and 4 turn ON-OFF every 60 ms, and only input from lighting switch system is accepted.
Wiper Dial Position Setting
Front wiper intermittent operation delay interval is determined from a combination of 3 switches (intermittent operation dial position 1, 2, and 3) and vehicle speed signal.
After each intermittent operation delay interval, BCM sends front wiper request signal to IPDM E/R.
Example: For wiper dial position 1
Using combination switch reading function, BCM detects ON/OFF status of intermittent operation dial positions 1, 2, and 3.
When combination switch status is as listed below, BCM determines that it is wiper dial position 1.
- Intermittent operation dial position 1: ON (Continuity exists between combination switch output 3 and input 1.)
- Intermittent operation dial position 2: ON (Continuity exists between combination switch output 5 and input 1.)
- Intermittent operation dial position 3: ON (Continuity exists between combination switch output 4 and input 2.)
BCM determines front wiper intermittent operation delay interval from wiper dial position and vehicle speed, and sends wiper request signal (INT) to IPDM E/R.
CAN Communication System Description
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-board multiplex communication line with high data communication speed and excellent error detection ability. Many electronic control units are equipped onto a vehicle, and each control unit shares information and links with other control units during operation (not independent). In CAN communication, control units are connected with 2 communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only.
CAN Communication Unit
Refer to Information Bus. CAN System Specification Chart